The present invention relates to a gear pump and method of using same, which gear pump has at least two rotors which mesh in an externally toothed manner in a product duct.
In the case of gear pumps with externally toothed, closely meshing shafts, considerable local pressure peaks occur during the squeeze-out operation to the pressure side caused by the entering of a tooth of the driven shaft into the corresponding tooth space on the non-driven shaft. During the delivery of higher viscous media, such as polymer meltings, these squeeze pressures reach peak values of several 100 bar. This extreme pressure rise, although it is short, results in considerable thermal stress and shearing stress to the delivered medium.